This invention is related generally to the field of fluid tank loading and, more specifically, to apparatus for improving the safety and ease of such tank loading.
Fuel oil used to heat buildings is generally stored in small tanks located either inside the building, outside the building or in the ground near the building. The loading of these tanks is typically done by local distributors who fill the tanks from filling trucks. The trucks are driven to a building, and a hose with a nozzle unrolled from a spool and brought to a fill pipe. Once the cap of the pipe is removed, the nozzle is inserted into the pipe, and the fluid product is transferred by pump into the fill pipe and, ultimately, into the tank.
Caps on the fill pipes typically screw onto threads on the fill pipe, and usually have an integral nut that allows a wrench to be attached to loosen a stuck cap. The wrench may be separate, or maybe integrated with the inside of the dispensing nozzle. Most commonly, caps are tightened by hand, and therefore a wrench is used only if a cap is stuck, after which the cap is removed by hand.
In response to fears that children, or other unauthorized persons, would remove the caps to oil tanks, a locking cap was developed that is described in U.S. Pat. No. 4,223,799. The cap itself is non-magnetic, but includes a vertically movable lock member that is susceptible to a magnetic force. Relying on the fact that most fill pipes are vertical, the lock member resides, under the force of gravity, in a position that prevents the rotation of the cap when mounted on the pipe. In particular, a fitting on the top of the pipe has recesses within which the lock member can fall. When the lock member resides within the recesses, rotation of the cap relative to the pipe is inhibited, thereby preventing its removal. Through the use of a magnet, the lock member is drawn up and out of the recesses of the pipe fitting. This allows the cap to be rotated and removed. A magnetic lock for the cap to the fill pipe is therefore created.
In accordance with the present invention, a fluid transfer nozzle is provided that allows for one-step removal of a locking cap from an input port. The caps in question include a detent mechanism that is movable under the influence of a magnetic field from a locked position to an unlocked position. In the locked position of an example cap, the detent mechanism is drawn by the force of gravity into engagement with obstructions on the inside of the input port, which is typically oriented with the cap on top. That engagement inhibits rotation of the cap relative to the input port. The caps may also include a nut-shaped protrusion, typically from the top of the cap.
The fluid nozzle of the present invention has a socket that engages the cap in a manner that prevents relative angular movement between the socket and the cap. Preferably, the socket is located in the mouth of the nozzle, such that placing the nozzle mouth over the cap allows the socket to engage the nut-shaped obstruction of the cap. The nozzle also includes a magnetic element that, when the socket engages the cap, is in sufficiently close proximity to the detent mechanism to cause movement of the detent to the unlocked position. With the detent mechanism moved to the unlocked position, the nozzle may be rotated with the socket still engaged with the cap. This, in turn, rotates the cap to the point at which it may be removed from the input port. The nozzle is then replaced on the top of the input port, and the fluid product dispensed through it.
In the preferred embodiment, the fluid product is fuel oil and the input port is the input to a vertical pipe leading to a fuel oil tank. The input port includes a top region in which angular obstructions extend inward from an inner surface of the pipe, creating obstructions engaged by the detent mechanism in the locked position. The detent mechanism inside the cap can move vertically when in place on top of the input port, and falls into engagement with the obstructions under the force of gravity. The magnetic element is preferably a permanent magnet located in the mouth of the nozzle adjacent to the socket. The magnetic field of the permanent magnet is sufficient to lift the detent mechanism to the unlocked position when the socket engages the cap.